Processing a milky way arch in Hugin

Hi Everyone,

With the core of the milky way about to become more visible at a reasonable hour of the night fast approaching I’m seeking any advice on using Hugin to stitch together a milky way arch.

Now, in my first attempt last year I set up the camera on a tripod and simply moved a few degrees around each image.

The lens is a 16-35mm and I had the camera in portrait orientation.

I’ve not been at all successful in joining the images together in hugin, so I expect that I either don’t know what I’m doing in the software, or I haven’t captured the images correctly to allow stitching to be completed.

So to avoid the mistakes I’ve made so far, does anyone want to have a look and provide any advice?

To save space and time, I’ve processed the images to jpeg in Rawtherapee. Happy to upload the raw images if you think that makes a difference.

Many thanks in advance.

Are you creating the control points by hand? If you’re using Hugin’s auto-creation, you’re likely to get poor results as you’ll get some control points on the horizon, and some in the sky. Since the sky is moving relative to the ground, this will cause you no end of trouble.

I’d like to take a stab at processing them, I should have some time tomorrow. Just quickly, what settings did you use when you exported them? Did you do any vignetting correction or lens distortion correction?

Hi Karl,

To be honest, I didn’t do any distortion or vignetting correction.

[Edit] - I just checked and they were corrected for distortion and vignetting.

Happy to post the raw files if desired, I just mindful of the size and the number of images, I did use a dark frame, but that should only help with dead pixels and noise I think.

I have tried doing the control points myself and letting Hugin pick them.

I’ll revisit this again with both done and try again with manually selecting the control points.

Peter.

Did you use a panorama tripod head?

Nope, normal ball head, locked the ball but shifted it using the panning bit…

Discuss seems to block .pto files, so here is a txt you can rename to .pto:
6bf971d258058f2cbcd55c467de851a2bc8d84c1 - de8abadd64aac380fec3899cef0f39cd06965cf2.txt (101.9 KB)

From what I can tell there are a few issues:

  • Some vignette and distortion in the images has not been corrected
  • There seem to be some optical issues toward the edges, maybe stop down a bit more
  • the really strange one, the images are misaligned in a way that seems to imply that the earth is turning beneath your feet

From what I can tell the seem slicing does a decent job of hiding this in the final image so for as long as you don’t want to have any details in the foreground this should be good enough. If you want more detail in the foreground you neeed to be either quicker or align twice, once for the foreground and once for the background then blend the two images. This can be done in hugin using masks.

I hope that is of some help. Enjoy the night skies. :slight_smile:

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This is to be expected - the images are 15 seconds each, which means that even if there was no time between the images, there is more than two minutes between the first and the last image. The night sky moves much faster than we realize. :slight_smile:

OK, thanks.

As @Jonas_Wagner mentioned, there is still a lot of barrel distortion that Hugin needed to correct. If you were going to re-process, perhaps think about including TCA correction.

I don’t think a pano head would be of any help here, as everything that would be affected by parallax is underexposed and should be cropped off. If you were doing this with a prominent forground object I would just mask it out.

Here’s my go. I let Hugin create the control points, but I restricted it to just adjacent images rather than letting it attempt to find points across all images. I then went through and deleted all the points in the ground, and created a couple of lines at the horizon to anchor it.

plaven_milky_way.txt (10.9 KB - rename to .pto)

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:open_mouth::open_mouth::open_mouth::open_mouth::open_mouth:

Wow!!!

Seriously just WOW! I never came close to anything like these images!

I’ll definitely revisit the images in RT again and make sure all have lens correction applied to them.

Did you use auto align or did you have to manually pick suitable control points?

Every time I tried I would get lost with playing with the sphere and crop… it really started doing my head in.

After a bit of time looking at another Hugin example on here I did a bunch of reading on parallax distortion. But as @Karl noted the movement in the milky way over two minutes is quite impressive, so that remains a challenge. And I did take a quite a few images thinking it would make the overlap better to work with.

I’ve seen some impressive results with people using Microsoft’s ICE. It seems fairly straightforward and I was looking at what can be done with the open source side of things. Clearly it can be done, just have to know how to work it.

Thanks again for taking the time to do this, it really showed me not all is lost. :slight_smile:

That’s impossible!!! The earth is flat and stays motionless at the centre of the Universe! :wink:

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Neither. I let Hugin create control points between pairs of adjacent images, then deleted any points that fell in the foreground. I only use the GL window (sphere and crop) as a preview.

Why Fiseye projection?

This was just a quicky. I wanted to have the horizon at ground level mostly straight and the milkyway arched. Other projections will probably work just as well if not better.